Hi ALL,

I have also tried this thing , but i couldn't display image ..

component:

<aura:component controller="PicGalleryCardCtrl" implements="flexipage:availableForAllPageTypes,force:hasRecordId"
                access="global">

    
    <aura:attribute name="fullScreen" type="Boolean" default="false"/>
    <aura:attribute name="animations" type="Boolean" default="true"/>
    <aura:attribute name="recordId" type="String"  />
    <aura:attribute name="slides" type="String[]" />
    <aura:attribute name="slideIndex" type="Integer" default="0"/>
    <aura:attribute name="slideWidth" type="Integer" default="0"/>

    <aura:handler name="init" value="{!this}" action="{!c.doInit}" />

    <lightning:card iconName="utility:image" title=" Picture Gallery">
        <aura:set attribute="actions">
            <lightning:buttonIcon onclick="{!c.fullScreen}" size="large" iconName="utility:expand" />
        </aura:set>
      <aura:if isTrue="{!v.fullScreen==true}">
            <div role="dialog" tabindex="-1" aria-labelledby="header43" class="slds-modal slds-fade-in-open">
                <div class="slds-modal__container">
                   <div aura:id="gallery" class="gallery">
        <div class="filmstrip" style="{! 'margin-left: -' + (v.slideIndex * v.slideWidth) + 'px'}">
            <aura:iteration items="{!v.slides}" var="slide" indexVar="index">
         
             <div class="slide">
                 
                    <img src="{!slide}"  alt="Placeholder" />
                  
              
                      
             </div>
            </aura:iteration>            
        </div>
        <div class="{! v.slideWidth>640 ? 'btn prev x-large' : 'btn prev'}">
            <lightning:buttonIcon variant="border-filled" onclick="{!c.prev}" size="large" iconName="utility:chevronleft" />
        </div>
        <div class="{! v.slideWidth>640 ? 'btn next x-large' : 'btn next'}">
            <lightning:buttonIcon variant="border-filled" onclick="{!c.next}" size="large" iconName="utility:chevronright" />
        </div>
    </div>
       
                </div>
                
                <div class="btn slds-modal__close close x-large">
                    <lightning:buttonIcon variant="border-filled" onclick="{!c.closeDialog}" size="large" iconName="utility:close" />
                </div>
                
            </div>
            <div class="slds-backdrop slds-backdrop--open"></div>
        </aura:if>
    </lightning:card>

</aura:component>


server - ctrlr
global with sharing class PicGalleryCardCtrl
{

 @AuraEnabled
public static List<String> getImageUrls(Id parentId)
{
  
    List<String> ImgUrlsList=new List<String>();
   
   
    for(Attachment att : [select Id, Name, ContentType from Attachment where parentid=:parentId and ContentType in ('image/png', 'image/jpeg', 'image/gif')])
   {
       ImgUrlsList.add('/servlet/servlet.FileDownload?file='+att .id);
    }
   return ImgUrlsList;
}
}